The FBI defines robbery as the taking, or the attempted taking, of anything of value from someone by force, threat of violence, or fear. Most robberies involve the use of a firearm and yield $1,190 worth of goods on average. There were 327,374 robberies reported nationwide in 2015 — 102 per 100,000 Americans.

Crime and crime rates vary greatly across U.S. cities. In the San Diego-Carlsbad, California metro area, 2,802 robberies were reported in 2015. The area’s robbery rate of 85 incidents per 100,000 residents is lower than than both the national rate and lower than the statewide rate of 135 incidents per 100,000 residents.

San Diego’s low incidence of crime is not limited to robberies. There were also three murders, 211 aggravated assaults, 1,922 property crimes per 100,000 city residents last year, all lower than the corresponding national crime rates.

There are several social and economic factors that are associated with crime. According to Nancy La Vigne, director of the Justice Policy Center at nonprofit economic and social policy research organization the Urban institute, the presence of opportunities for legal, gainful employment in a metro area is one of the primary deterrents to crime.

The more residents have access to legal means of income, the less likely they may be to turn to crime. One such indicator of access to legal means of income is the annual unemployment rate. Those unable to find work are among the most likely to commit a crime, out of either financial necessity or other motivations. An estimated 5.2% of the San Diego workforce was unemployed in 2015, roughly similar to the 5.3% national annual unemployment rate.

Like most metropolitan areas, San Diego’s unemployment has declined over the last half decade. Since 2011, the annual unemployment rate in San Diego has fallen by 5.1 percentage points — a greater improvement than the nation as a whole. Over the same period, the number of reported robberies fell by 8.1%, roughly similar to the 7.7% drop in robberies nationwide.

Young males between the ages of 15 and 24 are more likely to be criminals than any other demographic group. In San Diego, 7.9% of residents are between the ages of 15 and 24, a larger share than the 7.0% of Americans who are males of the same age group.